Speaker
Description
We report a precise measurement of the sub-GeV atmospheric gamma-ray spectrum at balloon altitude on GRAINE 2018 experiment, and comparisons with the predictions calculated by the latest HKKM, which is widely known as a model for atmospheric neutrino flux calculation.
Understanding the interactions between cosmic rays and atmospheric nuclei is important for accurate atmospheric neutrino flux calculations. Observation data of sub-GeV atmospheric gamma rays at balloon altitudes are useful for verifying such hadronic interaction models and pion productions in the low energy region.
In April 2018, we conducted a balloon experiment (GRAINE 2018) in Australia with the aim of detecting and imaging cosmic gamma rays with the nuclear emulsion telescope. Following flight data analysis, we derived an atmospheric gamma-ray spectrum in 0.1-1 GeV region at altitudes of ~36 km (residual depth ~4 g/cm$^{2}$). The flux around the 1 GeV region is in good agreement with the HKKM prediction and smoothly connects to the multi-GeV observations of past balloon experiments. On the other hand, the flux around 0.1 GeV shows a discrepancy with the prediction.
In this presentation, the balloon experiment, flight data analysis, and observation results will be described in detail.
Keywords
atmospheric gamma ray; hadronic interaction; atmospheric neutrino; balloon experiment; nuclear emulsion
| Subcategory | Experimental Results |
|---|---|
| Collaboration | other (fill field below) |
| other Collaboration | GRAINE |
